The present invention is related generally to stain removing compositions for promoting dental hygiene, more particularly to dental stain removing compositions containing a novel combination of stain removing agents and methods of making and using such compositions.
Unblemished white teeth have long been considered cosmetically desirable. Unfortunately, in the absence of thorough dental cleaning, teeth can become discolored or stained from chromogenic (color-causing) substances present in food, beverages, tobacco, and the like, and internal sources such as blood, amalgam-based fillings, and antibiotics (e.g., tetracycline). The tooth structures that are generally responsible for presenting a stained appearance are enamel, dentin, and the acquired pellicle. Tooth enamel is predominantly formed from inorganic material, mostly in the form of hydroxyapatite crystals, and further contains approximately 5% organic material primarily in the form of collagen. In contrast, dentin is composed of about 20% protein including collagen, the balance consisting of inorganic material, predominantly hydroxyapatite crystals, similar to that found in enamel. The acquired pellicle is a proteinaceous layer present on the surface of tooth enamel which reforms rapidly after an intensive tooth cleaning.
Discoloration of teeth can result from extrinsic and/or intrinsic staining. Extrinsic staining of the acquired pellicle arises as a result of compounds such as tannins and other polyphenolic compounds that have become trapped in and tightly bound to the proteinaceous layer on the surface of teeth. Discoloration from this type of staining can usually be removed by mechanical methods of tooth cleaning. In contrast, intrinsic staining occurs when staining compounds penetrate the enamel and even the dentin, or alternatively, such staining arises from sources within the tooth. Discoloration from intrinsic staining is not readily amenable to mechanical methods of tooth cleaning. Chemical methods, which utilize substances that can penetrate into the tooth structure, are usually required to eliminate such discoloration. Accordingly, intrinsic tooth staining is generally more intractable and difficult to address than extrinsic tooth staining.
Currently, there are a number of basic methods for removing stains in teeth. These methods are generally based on the use of abrasives, hydrolytic agents or oxidizing agents to break down the staining material. The first method involves mechanically abrading the stain through the use of harsh abrasives or polishing agents normally employed in toothpaste preparations. Typical preparations containing abrasives are toothpastes, gels or powder dentifrices, which require close contact with the teeth. Brushing and similar scrubbing or polishing action is typically required as a complement to successful stain removal. In the second method, hydrolytic agents including proteolytic enzymes can be used to whiten teeth. These products are usually in the form of pastes or gels, and function to whiten teeth by removing the plaque and calculus that have entrapped the stain.
Oxidizing agents such as urea peroxide, hydrogen peroxide or calcium peroxide, represent the most common forms of whitening agents for tooth enamels. It is believed that peroxides whiten teeth by releasing hydroxyl radicals capable of breaking down the plaque/stain complex into a form that can be flushed away or removed by an abrasive. Treatments using oxidizing agents typically require significant time to achieve good results depending on the peroxide source and its concentration.
Other active stain removing components including surface active agents such as anionic surfactants (see U.S. Pat. Nos. 6,485,739; 6,471,945; and 6,479,071), and chelators such as polyphosphates have been incorporated into stain removing compositions because of their good stain removing properties. However, such components have a few drawbacks. For example, excess amounts of surfactants can produce an undesirable soapy taste in the composition. Chelators also provide good stain removal activity, however, if added in excess amounts, can also negatively affect the taste (e.g., salty, bitter, and metallic) of the composition. Accordingly, although chelators and surfactants are good stain removing agents, the amounts that can be added to the composition are limited to avoid or minimize the problems discussed above.
It would therefore be a significant advance in the art of dental whitening to provide a composition capable of removing stains from dental surfaces, while maintaining desirable organoleptic and taste properties. It would be a further advance to provide a composition, which may be administered to a warm-blooded animal including humans through a convenient vehicle at any time. It would be a further advance in the art to employ chewing gums and confectionery compositions as an effective vehicle for delivering stain removing agents to the teeth because they permit protracted contact of the stain removing agents to the teeth with minimal effort on the part of the warm-blooded animal and are convenient for the warm-blooded animal to use at any time.